Republicans on the House Oversight and Government Reform Committee went after IRS Commissioner John Koskinen again Monday, while Democrats on the panel reserved much of their ire for Chairman Darrell Issa.

Issa, involved in a high-profile clash earlier this year with Elijah Cummings, the senior Democrat on the panel, was criticized repeatedly during Monday's hearing by Democrats who dismissed the proceeding as election-year posturing.

At one point, the California Republican warned Democrats that House rules forbid members from questioning the integrity or motives of other members — touching off a heated protest from Rep. Steven Horsford. The Nevada Democrat angrily contrasted Issa's admonition Monday with the March 5 incident, in which Cummings' microphone was turned off mid-statement on Issa's orders.

Issa repeatedly cut Horsford off, insisting the lawmaker "state a point of parliamentary inquiry," until Cummings broke in and asked the chairman to "Let him ask the question."

"I will not," Issa said.

The contentious exchange between the two African-American congressmen and Issa, who is white, was reminiscent of the hearing in March, which was also on the IRS and the agency's targeting of conservative political groups. After that incident, the Congressional Black Caucus asked the House to condemn Issa and asked Speaker John A. Boehner to strip Issa of his chairmanship, though no action was taken.Other Democrats, including Jackie Speier of California, John F. Tierney of Massachusetts and D.C. Del. Eleanor Holmes Norton, decried Issa's handling of the proceedings and the panel's treatment of Koskinen.Speier threatened to walk out of the hearing over what she called "badgering" of Koskinen, a former Clinton and Bush administration official who came out of retirement last year to lead the Obama administration's effort to clean up the tax agency in the wake of the targeting scandal.But Republicans have accused Koskinen and the IRS of being less than forthcoming with information about the targeting of conservative political groups and during Monday's hearing repeatedly hammered Koskinen, 74, over the lost emails of Lois Lerner, the former IRS official at the center of the investigation.
Koskinen notified Congress last week that some of the Lerner emails subpoenaed by Issa may be irretrievable because the former official's computer crashed in 2011 and was discarded and recycled, per normal IRS procedures. Former prosecutor Trey Gowdy, the South Carolina Republican who has also been named to head the House special committee looking into the 2012 terror attack in Benghazi, Libya, relentlessly questioned whether the IRS had mishandled or destroyed evidence in what potentially could be a criminal case.

"How would you know what elements of the crime existed?" he demanded of Koskinen, "You don't even know what statutes are in play. You don't have any idea."

Koskinen, unflappable through most of the more than three hours of questioning, seemed flustered by Gowdy, even acknowledging at one point that Gowdy had "a good argument" that the White House had inserted politics into the IRS investigation.

Monday's hearing came three days after Koskinen was put through a similar wringer by the House Ways and Means Committee, where Rep. Paul D. Ryan told the commissioner: "Nobody believes you." The hearing recessed at about 11 p.m. and is set to resume Tuesday morning.